In C6-3 Districts without a letter suffix in Mandatory Inclusionary Housing Program Area 4, as of February 14, 2018, in Community District 1, in the Borough of the Bronx, for MIH developments or affordable independent residences for seniors, the residential floor area ratio shall be that for an R9-1 District set forth in paragraph (d) of Section 23-154 (Inclusionary Housing) or in Section 23-155 (Affordable independent residences for seniors), as applicable.